Panel counting, collecting and gating method

ABSTRACT

A continuously conveyed series of uniformly dimensioned panels of thin sheet material are counted and stacked from the bottom against an abutment edge of a stationary but rotatable cam plate. When a predetermined number of panels is collected in the stack, the cam plate is rotated to lift the stack into a rotating roll nip for conveyance to a second roll nip. Removal of the stack from the proximity of the collecting cam plate is completed by the second roll nip after the collecting cam has resumed a stationary, collecting position.

United States Patent [191 Nikkel [451 Mar. 18, 1975 PANEL COUNTING, COLLECTING AND GATING METHOD [75] Inventor: Willem A. Nikkel, Covington, Va,

[73] Assignee: Westvaco Corporation, New York,

[22] Filed: July 23, 1973 [21] Appl. No: 381,891

Related U.S. Application Data [62] Division of Ser. No. 184,875, Sept. 29, 1971, Pat.

[52] U.S. Cl 214/152, 93/93 C, 93/93 DP, 214/6 BA, 271/212 [51} Int. Cl. 865g 57/30 [58] Field 01' Search 214/6 BA, 152; 93/93 C, 93/93 DP; 198/35, 40; 271/53 R, 60, 212

[56] References Cited UNITED STATES PATENTS l/1963 Bach 271/4 X 9/1964 Dale et a1 2l4/6H X 7/1965 Larsson 271/212 X 3,391,777 7/1968 Joa 198/35 3,587,413 6/1971 Sarka 93/93 C 3,596,575 8/1971 Brockmul1er.... 93/93 DP 3,636,316 l/l972 Suzuki et al. i 271/53 X 3,688,890 9/1972 Brockmuller 198/35 Primary Examiner-Albert J. Makay Assistant ExaminerL. .l. Paperner Attorney, Agent, or Firm- W. Allen Marcontell Richard L. Schmalz [57] ABSTRACT A continuously conveyed series of uniformly dimensioned panels of thin sheet material are counted and stacked from the bottom against an abutment edge of a stationary but rotatable cam plate. When a predetermined number of panels is collected in the stack, the cam plate is rotated to lift the stack into a rotating roll nip for conveyance to a second roll nip. Removal of the stack from the proximity of the collecting cam plate is completed by the second roll nip after the collecting cam has resumed a stationary, collecting positron.

3 Claims, 6 Drawing Figures TENTED MAR 1 8 M5 SHEET 1 Bf 2 PATENTED W1 8 5 SHEET 2 2 if TE mj Jilwl 1 u w m H mm km 3 mm H PANEL COUNTING, COLLECTING AND GATING METHOD CROSS REFERENCE TO RELATED APPLICATION The present application is a division of my earlier application Ser. No. 184,875 filed Sept. 29, 1971 and now issued as US. Pat. No. 3,785,256.

BACKGROUND OF THE INVENTION Field of the Invention l. The present invention relates to the art of thin sheet material handling and more particularly to the paper converting industry wherein a paper web of indefinite length is drawn from a large roll and cut into small panels of more convenient size, a discrete number of the small panels being counted and collected in a face-to-face stack for protective packaging and distribution.

Description of the Prior Art 2. In the process of converting paper from large roll stock, as received from the finish end of a papermaking machine, to individual packages containing a select number of uniformly sized panels, it is customary to cut one rectangular panel dimension by slitting as the web is reeled from the roll. The other panel dimension is cut by rotary knives disposed transversel of the web length as the web is fed continuously thereto. If it is desired to collect these dimensional panels into face-to'face stacks containing some particular number of panels, it is desirable to count, collect and deliver the stacks as rapidly as received from the transverse cutter. In the past, it has been necessary to run the rotary knife and therefore the slit web supply at a speed below capacity due to the greater time required of the counting, collecting and delivery operations by prior art methods.

One such prior art method is that disclosed by US. Pat. No. 2,708,760 to Lewis C. Pearce. The significant shortcoming of such prior art is the necessity to clear a completed stack of panels from the collecting station before the arrival of the first panel of the next stack.

It will be appreciated that the lateral structural integrity of an aligned stack of paper panels to resist shear separation is sustained only by the surface friction between individual sheets. When the stack is accelerated from the static collecting position by a dynamic force frictionally applied to the bottom panel, inertia of the stack resists such acceleration. Any given stack of panels, therefore, has a maximum lateral acceleration value whereat the opposite acting inertia force exceeds the frictional force holding the stack together.

Although, the frictional restraining forces may be augmented by accelerating the stack between a roll nip, even this expedient has a relatively low limit when compared to the velocity capacity of current panel supply systems. Long panels, rapidly supplied with short separation distances, quickly press the capacity of prior art systems due to the fact that the first panel of a new stack will close the separation gap between it and the last panel of a completed stack and become entangled therein before the completed stack may be removed from the collecting station. Accordingly the supply velocity must be reduced to a magnitude commensurate with that of the stack discharge period.

It is, therefore. an object of the present invention to provide a rapid response, counting, collecting and stack transfer method and mechanism wherein a succeeding stack may be started before the preceding completed stack is completely removed from the collecting station proximity.

Another object of the present invention is to provide a collecting and transfer method and mechanism wherein a completed stack discharge time period may overlap into the time period required to collect a predetermined number of panels.

A further object of the present invention is to provide a simplified collecting and discharge method and mechanism wherein the stack aligning fence is integral with the discharge propulsion roll.

SUMMARY The foregoing objects of the present invention are served by a rotary gate at the panel collecting station in the form of a notched cam wheel. Only the ends of the panel stack need be vertically supported by the notched cam.

Panel stacking at the collecting station is perferably from the bottom up from an endless belt conveyor having a break in the support plane at such a distance ahead of the notched cam as will allow the panel trailing ends to spring up and above the leading edge of oncoming panels.

Counting may be performed by any suitable means such as a photoelectric sensor which will emit a trigger signal to an electrically actuated single revolution clutch in the notched cam power train.

As the collecting notch in the cam rotates, the gate abutment is revolved away from the stack leading edge and simultaneously, the supported end portion of the stack is lifted into a roll nip between a constantly rotat ing overhead wheel and the back periphery of the cam wheel. This action is necessary only to transfer the stack end into a second, constantly turning, roll nip which completes the stack removal.

Meanwhile, the notched cam completes the one revolution transfer starting function and returns to the stationary collecting position where a new stack is begun even before the completed stack is completely removed from the collecting station proximity.

BRIEF DESCRIPTION OF THE DRAWINGS Relative to the drawing wherein like reference characters designate like or corresponding parts throughout the several views:

FIG. I is an elevational schematic of the invention in collecting position;

FIG. 2 is an elevational schematic of the invention in the initial stack transfer position;

FIG. 3 is an elevational schematic of the invention in the final stack transfer position;

FIG. 4 is a dimensional comparison chart relative to the panel length and cam wheel periphery;

FIG. 5 is an event sequence time comparison chart for the invention;

FIG. 6 is an isometric view of the notched cam showing the one revolution clutch in partial section.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring initially to FIG. 1, there is shown an endless belt conveyor 10 carrying a continuous series of thin sheet material panels P. The source of panels P is irrelevant as to this invention but in the normal use environment the panels are delivered with uniform longitudinal dimension L (FIG. 4) and serially separated by a gap G as the product of a continuous sheet web passing under a rotary shear.

Since the stated functional objective is to assemble the series continuum of single panels into face-to-face stacks, each containing a predetermined equal number of panels, it is necessary to first count the panels carried by the belt past a fixed point for the subsequent purpose of delineating a stack group for segregation. This counting function may be performed by many known devices which emit an electrical impulse when the set number of panels P pass the reference point and automatically reset to start the count over with the next successive panel. Selected for the purpose of this disclosure is a photoelectric relay device having a light emitter for directing a collimated beam 16 across the panel P conveyance path. A photon sensitive receiver l7 responds to each interruption of the beam 16 when a panel P passes thereacross by emitting a counting pulse. The series of counting pulses are received by a digital counting relay (not shown) which conducts a power signal when the predetermined number of count pulses have been accumulated. Upon conduction of the power signal, the digital counting relay circuit resets to start the count over again with the next successive count pulse.

A slight break is provided in the conveyance plane of belt 10 between sections 10a and 1019 as the belt 10 is drawn over turning roll 12 by the belt pulling roll 11 at the terminal end of the material transfer course. The length of belt section 10b and the obtuse angular divergence thereof from section 100 is selected to give an overhanging projection 14 to the trailing ends of panels P above the belt section 100 approach to the plane angle break point around turning roll 12. An air jet from conduit 13 supplements the material rigidity of panels P to hold the ends 14 above the approach plane 10a and further to gently urge the leading ends of pan els P to a flat entrance position into the wedge thereby accumulating a stack of panels S from the bottom.

It is important to specify a belt 10 providing a static frictional force between the surface thereof and a contiguous panel P face that is greater than the maximum dynamic frictional force between panels so that belt section 10a will deliver the final panel of a stack S to its properly aligned position against the leading edge abutment fence 22 in the notch 25 of gating wheel 20.

When the desired number of panels P have been accumulated, the counting system emits a power pulse to a single revolution clutch (FIG. 6) in the power train to cam wheel 20. As cam wheel revolves (FIG. 2), point A at the circular periphery thereof lifts the leading edge portion of the stack off the notch support surface 23. away from the fence portion 22, and into nip contact with the constantly rotating transfer nip roll 21. Due to the rapid response time of single revolution clutches of Type 6 as specified by Bulletin No. 239, January, I959, Hilliard Corporation, Elmira, N.Y., and the fact that not all of the stack S mass is subjected to acceleration parallel with the panel face shear planes, the surface velocity of cam wheel 20 has matched the surface velocity of transfer roll 21 by the time point A on cam wheel 20 reaches the nip position of FIG. 2. Thereafter, removal of the entire stack S from the holding position above belt section 10b is started.

As the circular periphery of cam wheel 20 between points A and B opposite from the notch 25 continues rotational nip cooperation with the transfer roll 21, the

stack S leading edge is delivered into the nip between constantly rotating removal rolls 30 and 31. Transfer table 26 between wheel 20 and roll 30 may be useful to prevent spreading of the individual panel ends during transfer from one nip to the other.

As removal of a completed stack 8 progresses under the nip propulsion of removal rolls 30 and 3|, the first panel P of the next stack continues unabated to advance along the final belt section 10b beneath the trailing end 14 of completed stack S toward the cam wheel 20 permissibly at a greater velocity than that of the withdrawing completed stack. Since cam wheel 20 is stopped after only one revolution, however, the fence 22 and end support surface 23 is quiescently awaiting the arrival of said next first panel. No interference is given the remaining portions of the withdrawing stack S due to the relief clearance allowed by the notch 25 in the stationary cam wheel 20 opposite from transfer roll 2]. Accordingly, the completed stack is leisurely drawn from the collecting station by the removal rolls 30 and 31 even after the next stack has accumulated several panels.

Although obvious to those of ordinary skill in art from the foregoing functional description of my invention, the disclosure hereof may be better served by an expanded explanation of certain design parameters and components. The first of such elucidations is represented by the dimensions C and D of FIG. 1. Since the only advancement ofa stack S given by nip cooperation between wheels 20 and 21 is to deposit the stack with the nip between rolls 30 and 3], it is necessary that are C of cam wheel 20 between points A and B opposite from notch 25 be at least equal or slightly greater than the centerline separation distance D between rolls 21 and 31. Moreover, as illustrated by FIG. 4, distance D is less than the length L of a panel P. The basis of these dimensional relations is to assure that one revolution of the cam wheel 20 will securely deposit a stack of length L within the propulsion nip between rolls 30 and 31.

Other critical parameters of my invention are the surface velocities of the belt 10 and the rolls 20, 21 and 30, 3]. These velocities are coordinated with the foregoing length parameters to yield a time-event sequence similar to that represented by FIG. 5. in that figure, dimenion 3 represents the maximum time lapse for one revolution of the cam wheel 20. Dimension d is that time period required to discharge a completed stack from the proximity of the collecting station at notch 25. Dimension d is the maximum period allowable for the discharge of such completed stack. Dimension 1 is the time lapse between the leading edge of one panel to the leading edge of the next successive panel. Dimension k is the time interim of a gap between the trailing and leading edges of two successive panels. Dimension s is the time required for the accumulation of a stack of 4 panels. Moments in the event sequence are measured from the trailing edge point of a stationary panel at the collecting station. At moment 0, the trailing edge of the last panel P of a stack S arrives at the reference point as represented by the minor lineations under time intervals I, through 1 Stacking interval s is complete and a simultaneous pulse from the counting relay engages cam wheel 20 to start the running of gating and discharge period g and d, respectively. The period g must be equal to or less than the period I so that when the trailing edge of the first panel of the next stack arrives at the reference point at moment 2, the cam wheel 20 is stationary in the collecting position. Since the invention precludes interference between the withdrawing stack and the newly accumulating stack, however, interval d may be extended beyond moment 2 to as much as moment 8 when the next succeeding stack is complete and ready for discharge.

A key element in the present invention is that of the single revolution clutch 40 shown by FIG. 6 in partial section. Power sleeve 41 is driven continuously be belt 42 running in sheave 43. Cam wheel drive shaft 44 is selectively engaged with the power sleeve 41 by a clutch mechanism 45 of the Sprag type which comprises a cage 46 for roller cams 47. The geometry of cams 47 is such that no rotational interference between race surfaces 41a and 44a is raised at one angular position of the cage 46 about the centerline thereof. When the cage is rotated to a second relative position, the cams 47 are wedged to a lock position between race surfaces 41a and 44a. The cage 46 is spring biased to the lock position. An abutment portion 48 on cage 46 is designed to cooperate with frame mounted pawl 49 when urged to the engaged position by spring 50. Disengagement of the pawl 49 from abutment 48 occurs at the instance of solenoid 51 actuated by the power pulse from the counting relay.

When the pawl 49 is in the engaged position, attempted rotation of the cage 46 thereagainst angularly displaces the cage 46 against spring bias to the first, free running, or disengaged position. Upon energization by a counting relay power pulse, the solenoid shaft 51a momentarily lifts the pawl 49 off the abutment 48. Cage spring bias angularly shifts the cage to the second, engaged position thereby transmitting rotary power to drive shaft 44. Since the counting relay pulse is only momentary, however, bias ofthe spring 50 immediately urges the pawl 49 back against the cage ring outer periphery 52 which slides thereon until contact with the abutment 48 is resumed after one complete revolution.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of the invention as set forth in the appended claims.

I claim:

1. A method of assembling panels of thin sheet material into face-to-face stacks comprising a discrete number of said panels, said method comprising the steps of:

a. delivering panels of thin sheet material in a substantially continuous series sequence to a collecting station;

b. counting said panels delivered to said station;

c. accumulating said panels at said station in a faceto-face stack by addition of panels to one face side of said stack;

d. aligning the leading edges of said stacked panels against an abutment element;

e. moving a leading edge portion of said stack upon the accumulation of a predetermined number of said panels in the direction of and substantially perpendicular to the other face side of said stack and into nip engagement between first and second rolls disposed for rotation about axes on opposite face sides of said stack; simultaneous with said leading edge moving step, rotatively withdrawing said abutment element about an axis coaxial of said first nip roll disposed on said one face side of said stack;

g. advancing said stack within said station by a single revolution of said first nip roll;

h. returning said abutment element to said panel edge aligning position simultaneously with the completion of said first nip roll single revolution; and,

i. removing said advancing stack from the proximity of said collecting station.

2. The method of claim I wherein said edge abutment element is returned to said edge aligning position before the removal of said stack from between said nip roll axes.

3. The method of claim 2 wherein the moving of said leading edge portion of said stack is initiated by delivery of said predetermined number of panels past a fixed reference point along the locus of said series sequence. l 

1. A method of assembling panels of thin sheet material into face-to-face stacks comprising a discrete number of said panels, said method comprising the steps of: a. delivering panels of thin sheet material in a substantially continuous series sequence to a collecting station; b. counting said panels delivered to said station; c. accumulating said panels at said station in a face-to-face stack by addition of panels to one face side of said stack; d. aligning the leading edges of said stacked panels against an abutment element; e. moving a leading edge portion of said stack upon the accumulation of a predetermined number of said panels in the direction of and substantially perpendicular to the other face side of said stack and into nip engagement between first and second rolls disposed for rotation about axes on opposite face sides of said stack; f. simultaneous with said leading edge moving step, rotatively withdrawing said abutment element about an axis coaxial of said first nip roll disposed on said one face side of said stack; g. advancing said stack within said station by a single revolution of said first nip roll; h. returning said abutment element to said panel edge aligning position simultaneously with the completion of said first nip roll single revolution; and, i. removing said advancing stack from the proximity of said collecting station.
 2. The method of claim 1 wherein said edge abutment element is returned to said edge aligning position before the removal of said stack from between said nip roll axes.
 3. The method of claim 2 wherein the moving of said leading edge portion of said stack is initiated by delivery of said predetermined number of panels past a fixed reference point along the locus of said series sequence. 